There are a number of 3rd party web sites and even a few iPhone apps that can link to your TiVo account in such a way that they can be used to schedule programs on your TiVo DVRs. They remain linked even after you change your TiVo username and/or password so they appear to use a kind of API key generated from your account.
From what I can tell, the only way to unlink them is from the 3rd party web site or application itself.
Is there a way to remove these links from TiVo's web site? If not there should be.
Right now there's a bug in the new i.TV app which won't let you unlink your TiVo account from the app once linked. What's worse is that the OAuth key appears to be stored online since the TiVo account remains linked after deleting and reinstalling the app. As such there's no way to remove the link between the app and TiVo as even after changing the TiVo password, the app can still schedule recordings.
i.TV also seems to send your TiVo account info over a http connection originally which is also bad.